Despite these similarities, the difference in the sequences of the individual genes, particularly the S protein, have led to the differential phenotypes and virulence between SARS-CoV-2 and the other SARSr-CoVs found in bats, civets and human in the previous epidemic, and hence different clinical manifestations of SARS and COVID-19 [142,143,144,145,146,147]. This evidence concerns the gene PROS1 and COVID-19.